Fluid pumps adapted for use in pumping liquids and fluids, such as oils and distillates produced from oil wells, frequently contain entrained contaminating materials such as sand, grit and the like. The pumping of such fluids results in the entrained gritty materials that are found in the fluid to come into contact with the pump elements, in particular, the pump surface elements as well as the pump bearings and seals. Where large volumes of fluid are pumped or a pump is used frequently, such as to empty a holding tank near the well site, the pump mechanical elements are exposed routinely to the entrained gritty materials. Consequently, pumps in service for such tasks have a tendency to wear prematurely and fail after a short period of use, such as after a few months or less than one year.
In the past, modular pump assemblies have been proposed to provide double fluid seals such as that disclosed by Korenblit in Canadian patent 2,021,157 which provides tandem mounted face seals each having a different construction, that is a flexible seal and a non-flexible seal to improve seal performance. Another seal arrangement is shown by Ernens in published Canadian patent application 2,226,693. The seal arrangement of Ernens situates the seals between the pump rotor and bearings. A high pressure hydraulic system and pump including high pressure seals at both ends of the pump driven shaft to reduce or eliminate forces that might tend to increase friction and wear is disclosed in published Canadian patent application 2,246,100 by Tieben.
However, to improve the serviceability of pumps and the increase the operating life of pumps put to uses involving pumping fluids containing grit materials, such as pumping field holding tanks of oil wells and the like, other pump assemblies are needed than have heretofore been provided. It is an object of this invention to provide a apparatus for modular pumps that provides for ease of maintenance and parts replacement of pump parts to decrease the cost of pump maintenance and to improve the life expectancy of the pump assembly.